Patient samples are often analyzed for the presence of analytes to determine if a patient is carrying a disease, has an infection, has been using drugs, etc. that may or may not be present in a patient's body. Analytes are typically detected with immunoassay testing using antigen-antibody reactions. Conventionally, such tests have been performed in specialized laboratories using relatively expensive reading equipment. However, the need for on-site examination at the point-of-care, such as hospitals, emergency rooms, nursing homes, practitioner offices, and even the home of the patient, is growing rapidly. Due to the expense and size of many laboratory test readers used to analyze such tests, conventional test readers are not generally suitable for use at the point of care.
Due to the limited sensitivity and breath of available point-of-care tests, turn around time of clinically significant diagnostic test results typically requires several days time. More specifically, tests must be completed at a central laboratory or be transferred to the laboratory where they are placed in a queue to be analyzed on one of a first-in, first-out or level of emergency basis. The delay of clinically significant test results may result in the delay of treatment until the presence of a particular ailment or level of a particular condition has been verified. For example, in an embodiment where a patient experiences the onset of a sore throat, a streptococcus (strep) screen is typically performed. Currently available rapid diagnostic, point-of-care test kits lack the sensitivity to detect an early stage of strep, and therefore, the patient typically waits two to three days for strep throat test results. Since doctors typically will not prescribe antibiotics or other remedies until the presence of strep has been verified in the patient, the recovery of the patient will be delayed and, in the meantime, the patient may come in contact with and infect a number of other individuals. Concerns are magnified in cases involving more serious medical conditions in which delayed treatment can have devastating effects.
As noted above, conventional point-of-care tests kits generally lack the sensitivity to detect conditions in early stages of development. This lack of sensitivity is due in part to the relatively low price points required for point-of-care testing. More specifically, point-of-care test kits have generally incorporate manual aliquot and manual read of the results. However, manual assay reading typically results in an increased error rate. In particular, in a pregnancy test using a lateral flow assay, the color of the lateral flow assay changes if the particular pregnancy hormone human chorionic gonadotropin, or HCG, is detected. In early stages of pregnancy, levels of HCG may be significantly lower than in later levels of pregnancy. Therefore, the lower levels of HCG will result in a less noticeable color change of the lateral flow assay than for a test completed when HCG levels are at a higher concentration. Since the human eye cannot readily differentiate between small color changes in the lateral flow assay, a user may mis-read the lateral flow assay therefore providing erroneous results, such as a false negative. The lack of sensitivity in point-of-care tests further increases dependency upon tests analyzed in the central laboratory.
In view of the above, a need exists for a point-of-care immunoassay test reader incorporating non-manual methods of immunoassay analysis with lower reading error rates. By lowering error rates, delayed treatment can be decreased or prevented. This prevention is important as delayed treatment may often lead to increased progression of an ailment, increased contamination levels of new individuals having contact with the patient, and other undesired effects. In addition, a need exists for such test readers that are not only increasingly sensitive and reliable, but that also can be provided at the low price points generally required for point-of-care equipment.